Is Parity Increasing in the NFL? An Early Look at the 2012 Season Trends

by Cameron Dowd

This year a disproportionate number of teams seems to be hovering around a mediocre .500 record. For instance, heading into this weekend, the entire AFC East was 3-3, another 6 teams had a 3-3 record, and five other teams were within one game of .500. This lead me to wonder whether there is more league wide parity this year than typically expected through six weeks of the season.

The first thing we need to determine is how to best judge team performance. Wins and losses – especially this early on in the season – are not the best indicator of performance; a better way to examine how teams are doing is to look at each team’s point differential; taking a team’s points scored minus its point against.

To determine whether this year is an outlier in terms of parity, I calculated each team’s point differentials for the past ten seasons through week 6 of the season.

To illustrate the difference in parity for this year compared to the past ten seasons I compared the histogram plots for point differentials for both the 2012 season and the 2011-2001 seasons.

2011-2001 Point Differential

The 2012 season’s histogram has a skew to the left while the 2011-2001 has a less pronounced left skew. It seems that the discrepancy between the two graphs is due to a higher number of teams with larger point differentials in 2011-2001 alongside a lack of such elite performance in 2012.

While it is not likely that a team in a typical year will post point differential through the first six weeks of the season on a level of the 2007 New England Patriots we would expect more teams on the higher end of the spectrum.

(For Fun Side Note: The 2007 season for the New England Patriots was truly remarkable. They scored an average of 38.3 points per game through the first six weeks of the season and won those contests by an average of 23 points. On the other end of the scale the 2002 Cincinnati Bengals were a dreadful team. They averaged 8.5 points per game through the first 6 weeks of the season and lost by an average of 21.67 points per game.)

This lack of elite teams is especially present in the AFC so far this season. The Houston Texans have posted the largest point differential at +58. While they blew out the Ravens last week, their terrible performance against the Packers two weeks ago shows that they, too, are vulnerable.

Additionally, the lack of elite point differentials cannot be explained by a lack of scoring league wide. In fact the first six weeks of the 2012 season have seen the most points scored of any year in the past ten seasons. For context the 4233 points scored through week 6 in the 2012 season is 145 more points than the second highest year (2011) and is 896 more points scored than the 2001 season.

While the 2012 season has followed the same historical trends for middling and poor performing teams, the lack of elite teams this season seems to indicate that the many teams are in the mix for contention this season. The New York Giants’ two recent Super Bowl runs have shown the importance of just getting into the NFL playoffs; once there, anything is possible. This year, with parity as measured by point differentials at a recent high, that lottery aspect of the NFL playoffs may be especially important.

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5 Responses to Is Parity Increasing in the NFL? An Early Look at the 2012 Season Trends

  1. Pingback: NFL Week 7 Power Rankings | Sport Skeptic

  2. uoduckfan33 says:

    Since the distributions are–at least–normalish, what do the standard deviations look like? Is there a statistically significant difference?

  3. ScottB says:

    Lol sample size

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